Disk apparatus

Abstract

According to one embodiment, a recording medium, a drive motor which supports and rotates the recording medium, heads, and a head actuator are arranged in a case of a disk apparatus. The drive motor includes a rotor rotatably supported by a fluid bearing and a stator arranged at an outer periphery of the rotor in a circumferential direction and having a plurality of magnetic poles confronting with magnetic poles of the rotor. The stator includes a removed portion which is located on a moving path of the heads and in which magnetic poles are removed in a range corresponding to 25% or less of the entire angle of 360° of the stator in the circumferential direction, a plurality of stator magnetic poles arranged at intervals in the circumferential direction except the removed portion, and a magnet attraction plate arranged in the removed portion and opposed to the rotor.

1 . A disk apparatus comprising: 
 a case having a base;    a disk-shaped recording medium arranged in the case;    a drive motor which rotates the recording medium, the drive motor being arranged on the base and supporting the recording medium;    heads which record and replay information to and from the recording medium; and    a head actuator which moves the heads with respect to the recording medium, the head actuator being arranged in the case and movably supporting the heads,    the drive motor including:    a rotor having a plurality of magnetic poles arranged side by side in a circumferential direction;    a fluid bearing rotatably supporting the rotor; and    a stator arranged at an outer periphery of the rotor in a circumferential direction and having a plurality of magnetic poles in confrontation with the magnetic poles of the rotor, and    the stator including:    a removed portion which is located on a moving path of the heads and in which magnetic poles are removed in a range corresponding to 25% or less of the entire angle of 360° of the stator in the circumferential direction;    a plurality of stator magnetic poles arranged at intervals in the circumferential direction except the removed portion; and    a magnet attraction plate arranged in the removed portion and opposed to the rotor.    
   
   
       2 . The disk apparatus according to  claim 1 , wherein the magnet attraction plate is formed by cutting and raising a part of the base.  
   
   
       3 . The disk apparatus according to  claim 1 , wherein the stator comprises a core configured by laminating a plurality of metal sheets, and a plurality of coils wound around the core, and 
 the core includes a base metal sheet formed annularly and having extending portions constituting the magnet attraction plate; and a plurality of lamination metal sheets each of which is formed to an arc shape, in which a portion corresponding to the removed portion is removed, the lamination metal sheets being laminated on the base metal sheet.    
   
   
       4 . The disk apparatus according to  claim 1 , wherein the drive motor includes a magnetic shield plate arranged on an outer peripheral side of the magnet attraction plate.  
   
   
       5 . The disk apparatus according to  claim 1 , wherein the head actuator includes: a bearing unit supported on the base; and suspensions rotatably supported by the bearing unit and extending from the bearing unit to support the magnetic heads.  
   
   
       6 . The disk apparatus according to  claim 1 , wherein the drive motor comprises: 
 a spindle shaft supported by the fluid bearing;    a hub fixed to the spindle shaft and constituting the rotor; and    an annular magnet fixed to the hub coaxially with the spindle shaft and constituting the plurality of magnetic poles, and    the recording medium is fixed to the hub and held coaxially with the spindle shaft.